A group of necromancers gathered to raise up an unstoppable army of the undead.
But something went horribly wrong.
The undead rose up against their masters and slaughtered them, and then went forth to conquer any who would oppose them.
That's the story behind Areetsa's Experiment 521KD.
The warrior himself is based on Areetsa's previous Kleinpanzer hardsuit, but here reworked into a fantasy castle setting.